Device for automatically effecting injections with a hypodermic syringe



Nov. 20, 1962 LEWIS DEVICE FOR AUTOMATICALLY EFFECTING INJECTIO WITH AHYPQDERMIC SYRINGE Filed April 15. 1959 2 Sheets-Sheet l Nov. 20, 1962D. 'r. LEWIS 3,064,650

I DEVICE FOR AUTOMATICALLY EFFECTING INJECTIONS WITH A HYPODERMICSYRINGE Filed April 15, 1959 2 Sheets-Sheet 2 United States PatentOhfice 3,%4-,h50 Patented Nov. 29, 1962 DEVIQE FQR AUTQMAIECALLYEFFECTING INJECTIONS WlTH A HYPODERMIC SYRHNGE Donald Travers Lewis,Port Lincoln, South Australia,

Australia; Elders Trustee and Executor Company Limited, and Grace Lewis,widow, executors of the estate of Donald Travers Lewis, deceased FiledApr. 15. 1959, Ser. No. 896,522 Claims priority, application AustraliaApr. 17, 1958 3 lairns. (Cl. 128-218) This invention relates to a devicefor automatically effecting injections with a hypodermic syringe.

When using hypodermic syringes it is necessary to insert the needle intothe patient for the required distance and then discharge the contents ofthe syringe through the needle, and when this operation is done by handthere is a large number of variables which are most undesirable andwhich are diflicult to control. Firstly, it is found that pain isexperienced and there is a tendency for the flesh surrounding the pointof injection to swell unduly and remain sore for some hours after theinjection is given if the needle is injected slowly, secondly it becomesnecessary in many cases to accurately gauge the depth to which theneedle will enter the flesh.

It will be seen that these two problems are diflicult to solve under anycircumstances, but when circumstances arise that a patient is requiredto give himself an injection it becomes quite diificult to control themto any appreciable extent and the patient is frequently subjected to agreat deal of unnecessary discomfort.

There are also other problems which it is the object of this inventionto overcome and these include the desirability of completing aninjection as quickly as possible and yet not forcing the injected liquidinto the body at a harmful rate.

Various proposals have been made to reduce or overcome some of the abovementioned faults with the injection system as at the present practisedand it is known that certain proposals have been made whereby ahypodermic syringe may pierce the flesh under the action of a spring.However, there are certain problems which are known to still exist, andamong these is the problem that occasionally a needle may be thrown fromthe end of the body of the syringe, and further that the previouslyproposed units are not always convenient to use.

A still further problem with the hypodermic syringes of the type inwhich the force to effect injection is transmitted to the syringe bodythrough the liquid contents, is that certain drugs should be injected ata depth beneath the skin which exceeds a predetermined minimum in orderto prevent irritation to the skin, and if a hypodermic syringe entersthe skin whilst its contents are being discharged, it is probable thatirritation will occur. It is a further object of this invention toprovide a means whereby discharge of a hypodermic syringe will notcommence until the needle is positioned beneath the flesh.

In brief the invention may be said to consist of a device comprising ahousing, a syringe carrier arranged to slide in relation to the housing,means on the carrier to confine a syringe within it against relativeaxial displacement, so that the needle of the syringe may projectforwardly from the carrier and the plunger may project rearwardly,spring means arranged to load the carrier so that it tends to move in aforward direction, a releasable trigger arranged to hold the carrierback against the spring loading, release means to release a pressuremember on forward movement of the carrier and means on the pressuremember to move the springe plunger forward within the syringe duringcontinued movement of the pressure member.

While it will be understood that constructional varia- Ill tions couldbe introduced which would still lie within the scope of the invention,an embodiment of the invention will be described with reference to theaccompanying drawings in which:

FIG. 1 is a perspective view of a device,

FIG. 2 is a longitudinal section to a slightly reduced scale, showing asyringe loaded in the device, and the device in its cocked position,

FIG. 3 is a view with the lid open, but without the syringe, and withthe device in a normal position, and

FIG. 4 is a section on lines 4-4 of FIG. 1.

The injecting device 1 is made with a pistol grip Z, a release trigger3, and a housing 4 of sheet metal. A syringe carrier 5 is constructed sothat the syringe 6 is supported at its front in a slot 7 which supportsthe nose or boss of the needle 3, and it is supported at its rear end ina second slot 9 which fits over the plunger 10. The slot 9 is in aslotted bracket 11 which is adjustably secured to the carrier 5 by thescrew threaded members 12, which at the same time serve to slidablyretain the carrier 5 to the housing 4.

A pressure rod 14, which may be of any suitable material, say threesixteenth inch diameter brass, extends for the full length of thehousing 4, terminating just behind the front face at its front end 15and projecting through the rear end of the housing 4 by a short distanceand terminating in a bridge member 16 which enables it to be cocked byhand. The bridge member 16 dso carries an actuating rod 17, theactuating rod 17 being made coaxial with the injection syringe 6.

The top surface of the syringe carrier 5 has an upwardly formed member18 with a hole 19 therein through which the pressure rod 14 projects.This member 18 is situated a predetermined distance back from the frontof the syringe carrier 5 so that the distance between the front of thesyringe carrier 5 and the front end 15 of the member 14 is approximatelythe length of stroke of the syringe plunge-r 10 when the device 1 iscooked.

The pressure rod 14 has a slot 21 cut in the top of its front end toengage a downwardly formed part of the latch member 22 which is urgedinto the slot 21 by the leaf spring 23, when pressure rod 14 and thesyringe carrier 5 are drawn rearwardly. A projection 24, preferably inthe form of a screw as shown in FIG. 3 engages the upwardly formedmember 18 so that the unit may be cooked by moving the bridge member 16rearwardly.

A slot 25 in the lower wail of the syringe carrier 5 co-operates with asear 26 which is urged upwardly by means of a scar spring (not shown)when the carrier 5 is withdrawn the desired amount. The trigger 3 isheld outwardly by spring 27, but when actuated releases the sear 26 fromthe syringe carrier 5 so that a spring 29 around the pressure rod 14urges pressure rod 14 forwardly at a high speed, this in turn urging thecarrier 5 forwardly, thus moving the needle 8 through the aperture 39 inthe housing 4- so that it may penetrate into the flesh, and when thecarrier 5 terminates its forward motion the pressure rod 14 is releasedfrom the hole 19 in the member 18 on the syringe carrier 5 by the latchmember 22 against a release ramp 32 on the inside of the housing 5, andthen the actuating rod 17, which is on the pressure rod 14 because ofthe bridge member 16, will push the syringe plunger 10 downwardly toinject the contents. A screw threaded adjusting member 33 is providedwith a flange 34- arranged to contact the outside of the housing 4 toadjust the foremost point of travel of the carrier 5 and thereby adjustthe depth of penetration of the needle 8.

A lid 35 is fitted to the side of the housing 4 to 0bscure the syringe6, this feature having a strong psychological efiect particularly onchildren who might otherwise be afraid of injections. The spring member36 retains the syringe 6 in the carrier when the 11d 35 1s closed.

It will be seen from this description that the carrier 5 is loaded in aforward direction by the spring 29 acting through the pressure rod 14.It will further be seen that the device 1 may be cocked 'by a singlemovement, and that the contents of the syringe 6 will not commence to beexpelled until the needle 8 has finished or almost finished its forwardmovement.

What I claim is: y

1. A device for automatically elfecting injections, comprising a housingincluding a pistol grip, a syringe carrier in the housing, syringeretaining means on said carrier arranged to axially confine a syringe insaid carrier with the needle of said syringe projecting forwardly andthe plunger of said syringe projecting rearwardly, an aperture'in theforward end of the housing in the path of travel of the needle,retaining means engaging the carrier but being'confined in a slot in thehousing whereby said retaining means siidably retains the carrier to thehousing, an adjusting member screwed into the carrier and extendingrearwardly through an aperture in the housing, a flange on saidadjusting member arranged to strike the housing upon forward movement ofthe carrier and to thereby limit said forward movement, a pressure rodslidable in the housing, a spring disposed around said slidable pressurerod bearing against the rear end of the housing to urge the pressure rodforwardly, a transverse slot in the pressure rod near its front end, alatch member on the carrier releasably engaging said transverse slot onsaid pressure rod whereby said spring loads said carrier forwardly, abridge member-on the rear end of said pressure rod, an actuating rod onsaid bridge member spaced from said presjsure rod but parallel thereto,a releasable trigger in the pistol grip to hold said carrier back, and aramp on the housing in the path of the latch member adapted to releasesaid latch member from said pressure rod after the first part of theforward movement of the pressure rod, said actuating rod being arrangedto strike the syringe plunger and move the plunger forward uponcontinued forward movement of the pressure rod under the influence ofthe, spring.

2. A device for automatically effecting injections, comprising a housingincluding a pistol grip, a syringe carrier in the housing, syringeretaining means on said carrier arranged to axially confine a syringe insaid carrier with the needle of said syringe projecting forwardly andthe plunger of said syringe projecting rearwardly, van aperture in theforward end ofv the housing in the path of travel of the needle, a screwand nut engaging the carrier but being confined in a slot in the,hOllSing whereby the nut slidably retains the carrier to the housing,an adjusting member screwed into the carrier and extending rearwardlythrough an aperture in the housing, a flange on said adjusting memberarranged to strike the housing upon forward movement of the carrier andto thereby limit said forward movefment, a pressure rod slidable in thehousing, a spring disposed around said slidable pressure rod bearingagainst the rear end of the housing to urge the pressure rod forwardly,a transverse slot in the pressure r-od near its front end of saidpressure rod, a latch member on the carrier releasably engaging saidtransverse slot on said wardly, a bridge member on the rear end of saidpressure rod, an actuating rod on said bridge member spaced from saidpressure rod but parallel thereto, said actuating rod passing through anaperture in the rear of said housing, a releasable trigger in the pistolgrip to hold said carrier back, a ramp on the housing in the path of thelatch member adapted to release said latch member from said pressure rodafter the first part of the forward movement of the pressure. rod, saidactuating rod being arranged to strike the syringe plunger and move theplunger forward upon continued forward movement of the pressure rodunder the influence of the spring. I

, 3. A device for automatically effecting injections, comprising a sheetmetal housing including a hinged lid and pistol grip, a syringe carrierin the housing, a syringe retaining slot in the front end of saidcarrier, and a slotted syringe retaining bracket towards the rear end ofsaid carrier arranged to axially confine a syringein said carrier withthe needle of said syringe projecting forwardly and the plunger of saidsyringe projecting rearwardly, an aperture in the forward end of thehousing in the path of travel of the needle, an elongated aperture insaid bracket, a screw securing the bracket to the carrier, said screwpassing through the elongated aperture in the bracket whereby thebracket is adjustably positioned on the carrier, a 'nut on the screw,the nut being disposed outside the housing, the nut engaging the carrierbut being confined in a slot in the housing whereby the nut slidablyretains the carrier to the housing, an adjusting member screwed into thecarrier and extending rearwardly through an aperture in the housing, aflange on said adjusting member arranged to strike the housing uponforward movement of the carrier and to thereby limit said forwardmovement, a pressure rod slidable in the housing, a spring disposedaround said slidable pressure rod bearing against the rear end of thehousing to urge the pressure rod forwardly, a transverse slot in thepressure rod near its front end of said pressure rod, a latch member onthe carrier releasably engaging said transverse slot on said pressurerod whereby said spring loads said carrier forwardly, a bridge member onthe rear end of said pressure rod, an actuating rod on said bridgemember spaced from said pressure rod but' References Cited in thefile ofthis patent UNITED STATES PATENTS 2,295,849 Kayden Sept. 15, 19422,472,116 Maynes June 7, 1949 2,671,448 Harnisch Mar. 9, 1954 2,816,546Luhmann' Dec. 17, 1957 FOREIGN PATENTS v 163,203 Australia June 3, 1955

